南海LH油田珠江组礁灰岩储层是重要勘探开发层位,储层下方的隔挡层b2裂缝发育程度直接影响生产井含水的上升速度。为了探索隔挡层裂缝发育情况,结合研究区成岩及构造特征,针对海上窄方位采集地震资料,运用地球物理裂缝检测技术,预测裂缝发育特征;同时对采用纵波方位各向异性裂缝预测方法、远近偏移距属性差异裂缝预测方法、叠前应力场预测方法分别进行适用性分析。叠前应力场检测裂缝的方向以平行于断裂的北西西向、垂直于断裂的北北东向为主;方位属性差异裂缝预测,对非平行于构造走向(北西西向)、非垂直于构造走向(北北东向)的裂缝敏感,对平行或垂直于构造走向的裂缝检测能力较弱;远近偏移距属性差异裂缝检测对非平行于构造走向(北西西向)的裂缝敏感,尤其对于垂直于构造走向(北北东向)的裂缝敏感。这3种裂缝检测方法既有重合也有互补,综合分析能够更准确地描述裂缝发育分布规律,成功预测隔挡层b2层及目的层裂缝分布特征。裂缝预测结果得到了生产井开发动态验证,主要隔挡层b2层预测的裂缝发育区,也是生产油井含水上升速度快的区域;裂缝相对不发育区,油井含水上升速度慢,产量比较稳定。研究区域生产井验证预测裂缝吻合率达到75%以上。
The reef limestone reservoir of Zhujiang Formation is an important exploration and development reservoir of the LH oilfield in South China Sea.The fracture development degree of Layer b2 beneath the reservoir directly influences the water rate of the production wells.In order to explore the fracture development situation,the geophysical fracture detective technology is used to predict the fracture features combined with the characteristics of the regional diagenesis and structure and on the basis of the marine seismic data gathered in the narrow azimuth.The applicability of AVAZ technology,the far-near offset attributes difference technology,and the stress field analysis technology based on pre-stacked data is analyzed and a suite of fracture detective technologies for gathering seismic data in narrow azimuth are summarized.Layer b2 and the reservoir fracture features are successfully predicted by the combination of these three different technologies.The main directions predicted by the pre-stacked stress analysis are WNW in parallel with faults and NNE perpendicular to faults.The fracture prediction technology using the differences of azimuth attributes is sensitive to the fractures not perpendicular to the structure,although it is not sensitive to the fractures in parallel with the structure.The fracture prediction technology using the differences of offset attributes is sensitive to the fractures in parallel with the structure,especially sensitive to the fractures perpendicular to the structure.These three methods both have the same points and the differences.In order to get the precise results,one must compare these three methods so that the distribution of Layer b2 and the targets fracture can be obtained.The fracture prediction result is testified by the production wells.It shows that the fracture development area of Layer b2 is also the zone of the production wells with the high-speed rising water.While in the area that fractures are not developed,the production wells have the slow-speed rising water,and t